Pump apparatus



July 23, 1963 F. P. HOPFELD 3,098,587

PUMP APPARATUS Filed April 14, 1960 2 Sheets-Sheet 1 F1 grl J m I a 68 'INVENTOR.

FRED P. HOPFELD F. P. HOPFELD PUMP APPARATUS July 23, 1963 2 Sheets-Sheet 2 Filed April 14, 1960 INVENTOR. FRED l HOPFELD which contains internal United States Patent Illinois 14, 196i), Scr. No. 22,194

Filed Apr.

1 Claim. (Cl. 222-176) This invention relates to hydraulic pump apparatus of the kind adapted to be manually actuated by a hand lever. This invention particularly relates to a hydraulic pump apparatus especially adapted to raise a load bearing carriage of a lift truck.

In Patent No. 2,885,96l there is illustrated and described a manually actuated and propelled lift truck of a kind which has found wide application in the materialshandling field, particularly in lifting and stacking materials in warehouses and the like. As described in the above-noted patent, such a lift truck embodies a support and carriage which is adapted to pick up articles at floor level, and a hydraulically actuated ram is utilized to raise the supporting carriage along a vertically extending frame of the truck.

It is a primary object of this invention to construct novel pump apparatus for use with a lift truck of the general kind described. Pumping apparatus constructed in accordance with the present invention includes a tank affording a reservoir for hydraulic fluid, a base member conduit and valve structure, and a pump cylinder which comprises an outer cylinder and a piston reciprocable therein. The base member is integrally joined in a side wall of the tank at one end thereof and projects outwardly from the side wall. cylinder is in turn integrally seated in a recess formed in the upper surface of the base member so as to project upwardly from the base member and alongside of the side wall of the tank to which the base member is joined. Inasmuch as the tank, base member, and cylinder are thus integrally joined with one another, the pump apparatus of the present invention affords a unitary structure which can be readily mounted on or removed from a lift truck or the like in a quite simple manner; and to incorporate the foregoing enumerated structural features in a novel pump apparatus are specific objects of the present invent-ion.

In the course of operation of a lift truck of the general kind described, the lift truck and the pump apparatus are apt to be tilted through a variety of angular positions. Also, in some cases and depending upon the particular application to which the pump apparatus is to be applied, it may be desirable to mount the pump apparatus in a horizontal or inclined position rather than in a normal vertical position. In such instances it will be recognized that problems may arise in maintaining a supply of fluid from the tank to the cylinder of the main pump structure. Accordingly, it is another object of this invention to locate an inlet passage-Way in the base member in a manner such that a supply of fluid from the tank to the interior of the cylinder is assured with the pump apparatus in any one of a variety of angular inclinations.

It is another object of the present invention to interpose a coiled screen in the inlet passageway to serve as a filter and in a manner such that the screen can be readily removed for cleaning or replacement.

The pump apparatus of the present invention incorporates check valves for insuring uni-directional flow from the tank and through the pump cylinder to an outlet opening of the pump apparatus. It is another object of the present invention to provide for ready access to such check valves from the outside of such pump apparatus.

Other and further objects of the present invention will 3,@%,58'i Patented July 23, 1963 "ice be apparent from the following description and claim and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what is now considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claim.

In the drawings:

FIG. 1 is a side elevation view of a lift truck showing a pump apparatus constructed in accordance with one embodiment of the present invention incorporated therewith;

FIG. 2 is an enlarged side elevation view of the pump apparatus shown associated 'th the lift truck illustrated in FIG. 1;

FIG. 3 is a side elevation view of another form of pump apparatus constructed in accordance with the present invention and adapted to be utilized With the lift truck illustrated in FIG. 1;

FIG. 4 is an enlarged elevation view, partly broken away, and taken in the direction of the arrows 4-4 in FIG. 2',

FIG. 5 is a sectional plan view taken in the direction of the arrows 5'5 in FIG. 4',

FIG. 6 is an elevation view in section taken in the direction of the arrows 6-6 in FIG. 2;

FIG. 7 is a fragmentary detail view showing a modified construction of a portion of the base member illustrated in FIG. 5;

FIG. 8 is a detail view, partially broken away, of a screen adapted to be utilized with the construction illustrated in FIG. 7; and

FIG. 9 is a plan view of a block member incorporated in the pump apparatus illustrated in FIG. 4 and taken in the direction of the arrows 9-9 in FIG. 4.

In FIG. 1 one form of a pump apparatus constructed in accordance with the present invention is shown associated with a lift truck of the general kind noted hereinabove. While the pump apparatus of the present invention is especially adapted for use with a lift truck such as that illustrated in FIG. 1, and will be hereinafter described with particular reference to the manner of association with such a lift truck, it should be noted that the pump apparatus of the present invention is not limited to use with such lift trucks. Instead, the pump apparatus of the present invention is readily adaptable for use in any application wherein a manually actuated hydraulic pump is desired. However, for purposes of disclosure, and to demonstrate the utility of the pump apparatus of the present invention, the pump apparatus of the present invention is shown as associated with a manually powered and operated lifting and stacking truck which is especially adapted for use in factories, shops, or warehouses wherein lifting and stacking operations as a type of material-handling operations are to be performed.

Thus, in FIG. 1 a lift truck is indicated generally by the reference numeral 21 and one form of a pump apparatus constructed in accordance with the present invention is indicated by the reference numeral 22. The lift truck 21 is like that described and illustrated in Patent No. 2,885,961 and comprises a vertically extending frame structure 23 and an article-supporting carriage 24 which is vertically movable along the frame structure 23 by a hydraulically actuated ram 26. Thus, the ram 26 includes a piston 27 which is movable within an outer cylinder of the ram, and a sprocket assembly 28 is carried on the uppermost end of the piston 27. A chain 29 is passed over the sprocket assembly 28 and is connected at opposite ends to the outer cylinder of the ram and the support carriage 24. Inasmuch as the outer cylinder of the ram is rigidly attached to and supported on a base plate 31, which forms a part of the frame structure 23, application of fluid pressure to the ram 26 is effective to move the piston 27 and sprocket assembly 28 upwardly to lift the support carriage 24.

In accordance with the present invention a novel pump apparatus is adapted to be directly and conveniently mounted on the frame structure 23 for supplying hydraulic fluid under the pressure to the ram 26 to effect such lifting of the support carriage 24 and thereby enable quite large and heavy objects to be vertically positioned with a minimum of physical etfort on the part of the operator of the lift truck 21. One form of the pump apparatus 22 constructed in accordance with the present invention is shown in separate detail in the various FIGS. 2, 4-6, and 9.

With particular reference to FIGS. 2 and 4, it is seen that the pump apparatus 22 includes a tank 32 which affords a reservoir for a quantity of hydraulic fluid. The tank includes a filler plug 33 in the upper surface thereof, which may be removed to enable hydraulic fluid to be added to the tank. The tank 32 is preferably of a generally rectangular configuration as illustrated, and one vertically extending side wall 32W' thereof is formed with an opening 34 in the lower portion thereof, which opening is coextensive with the length of the side wall 32W.

A base member 36 in the form of a rectangular block has one face 36F thereof inserted within the opening 34 so as to be in direct communication with the hydraulic fluid within the reservoir afforded by the tank 32. The base member 36 is integrally joined with the side Wall 32W in any suitable manner, such as by welding, soldering, brazing, or the like. As illustrated, the base member 36 projects in substantially perpendicular relationship from the side Wall 32W so as in effect to form a ledge or platform at one side of the tank 32.

As best illustrated in FIGS. and 6, it is seen that the base member 36 is formed with a circular recess 37 in the central portion thereof which recess includes a conically tapered base surface 573 afiording a shoulder at the juncture of the cylindrical side walls and conical base of the recess. With particular reference to FIG. 5 it is seen that the base member 36 is also formed with conduit means for transmitting hydraulic fluid from the tank 32 and through the recess 37 to an outlet opening indicated by the reference numeral 38. Thus, an

out-let opening 38.

The pump apparatus 22 also includes fluid-pressurizing means for pumping hydraulic fluid from the tank through the aforesaid passageways into the outlet opening 38. The fluid-pressurizing means include a tube 43 which is seated at its lower end portion in the recess 37 on the shoulder afforded by the juncture of the conical surface 37B with the side walls of the recess. The tube 43 thus extends vertically from the upper surface of the base member 36 in spaced relation from and alongside the side wall 32W of the tank 32 in the manner illustrated in FIG. 4 and is integrally joined to the base member 36, as by welding. The tube 43 aifords the outer cylinder of a hydraulic pump, and a piston 44 is axially reciprocable therein.

The fluid-pressurizing means also include check valves disposed within the passageways leading to and extending from the recess 37 for enabling pumping action to be obtained as an incident of such reciprocation of the piston 44 within the cylinder afforded by the tube 43. Thus, the passageway 41 includes a portion 41A of enlarged diameter so that an annular valve seat is formed at the juncture of the smaller and larger diameter portions of the passageway, and a ball check valve 46 is normally biased into fluid-flow blocking engagement with the valve seat by a coiled compression spring 47. The spring 47 is in turn seated at its opposite end on a shoulder formed on a seal plug 43 threaded within a tapped portion of the passageway 41A. In like manner the passageway 42. leading from the recess 37 is formed with a portion of enlarged diameter 42A which defines an annular valve seat with the smaller diameter portion of the passageway 42. A ball check valve 49 is biased to fluid-flow blocking engagement with the valve seat by a coiled compression spring 51 seated on a shoulder of a seal plug 52.

It will be recognized that movement of the piston 44 upwardly within the tube 43 is effective to draw hydraulic fluid through the inlet passageway 39 and past the check valve 46 into the interior of the tube 43. Subsequent downward movement of the piston 44 is then effective to unseat the check valve 49 and force fluid under pressure toward the outlet opening 38. The tube 43 is formed with an annular recess 53 in the inner surface adjacent the upperend thereof, and a backup seal 54 is disposed within the recess to prevent leakage of fluid between the tube 43 and the piston 44.

With continued reference to FIG. 5 it is seen that the base member 36 is formed with an additional passageway 56 which extends from the outlet opening 38 and opens in the face 46F of the base member which communicates with the interior of the tank 32. This additional passageway 56 affords a direct connection between the reservoir and the outlet opening 38, and thus the load device to which the hydraulic fluid under pressure is being supplied by the pump apparatus 22. Valve means are included in the pump apparatus 22 for regulating the flow of fluid through the additional passageway 56, and such valve means are indicated generally by the reference numeral 57 in FIG. 4.

tached to the base member 36. The block member 58 is formed with an L-shaped passageway 59' which has a horizontally extending portion in communication with the passageway 56 and a vertically extending portion which opens in a conically tapered base surface 61B of a circular recess 61 formed in the upper surface of the block member. A pipe or sleeve 62 is seated at its lower end within the recess 61 The pipe 62 is formed with a series of holes or perforations 71 extending radially therethrough so that rotation of the cap 63 by manipulation of the handle 64 is effective to move the rod 67 axially upwardly to permit fluid under pressure to flow from the L-shaped passageway 59 past the ball 69 and between the rod 67 and the interior of the pipe 62 back to the reservoir Within the tank 32.

Thus, the valve means 57 may be positioned either the reservoir. It will be recognized that the accurate positioning of the rod 67 afforded by the threaded construction of the cap 63 enables the flow past the valve 69 to be precisely regulated and this has the effect of enabling the carriage 24 of the lift truck illustrated in FIG. 1 to be lowered at a desired rate of travel.

While the passageways 59 and 56 are shown as directly communicating with each other in the construction illustrated in FIG. 4, in some instances it may be desirable to insert an auxiliary sleeve in the passageways 56 and 59. In such a case, the sleeve acts as a seal for minimizing leakage between the passageways 56 and 59 so that the block member 58 can be attached to the base member 36 by a series of spot welds rather than a continuous bead well. a

As illustrated in FIG. 1, the pump apparatus 22 is normally mounted in the vertical position illustrated. However, it is not essential that the pump apparatus of the present invention be vertically mounted in order to be operative. Thus, the pump apparatus of the present invention can as well be mounted in a horizontal position displaced 90 from that illustrated in FIG. 1, and the particular location of the inlet passageway with respect to the tank 32 enables such flexibility in the mounting of the pump apparatus to be obtained.

As illustrated in FIG. 5, the inlet passageway 39 extends forwardly at an angle from the passageway 41 so as to open in a portion of the face 36F which is closely adjacent the forward corner edge of the base member. Therefore, because the inlet opening for the passageway 39 is thus disposed closely adjacent the forward side wall of the tank 32, the inlet opening for the passageway 39 is at all times disposed beneath the level of the hydraulic fluid within the reservoir even though the tank is tilted back and forth between vertical and horizontal positions, and this disposition of the inlet passageway with respect to the tank 32 is an important feature of the present invention.

In FIG. 7 there is illustrated in fragmentary detail view a modified construction of the corner portion of the base member 35 which is formed with the inlet passageway. Insofar as the parts of the construction illustrated in FIG. 7 are like those illustrated in FIG. 5 like reference numerals have been used, but with the addition of a prime mark. Thus, the base member 36' includes a passageway 41 which affords a portion of the conduit means interconnecting the reservoir with the pump cylinder. However, in this instance an enlarged passageway 76 is formed in the base member 36' at a right angle to and in communication with the passageway 41. The enlarged passageway 76 affords a chamber for the reception of a filtering device. Thus, a piece of wire screen, such as the rectangular screen 77 illustrated in FIG. 8, can be rolled into a coil and inserted within the bore 76 so as to be interposed in flow-intercepting relation between the passageway 41 and a passageway 78 which, like the passageway 39 described hereinabove, opens closely adjacent the forward corner edge of the base member 36'. The screen is retained in position by a sealing plug threaded within the internally tapped outer end of the passageway 76. In this manner, all fluid passing through the inlet passage way to the cylinder 43 of the pump is filtered to remove any impurities before such impurities can cause damage to the operating parts of the pump apparatus. In practice a one hundred mesh brass wire screen has been :found to be quite effective as the filtering element. It will be recognized that the construction illustrated in FIG. 7 facilitates convenient endwise removal of the screen coil for cleaning or replacement.

As illustrated in FIG. 5 the base member 36 is preferably formed with circular holes 79 which extend therethrough for the reception of bolts or like fastening devices.

The pump apparatus of to be manually actuated to achieve the present invention is adapted the above-noted recip-rocable movement of the piston 47 within the tube 43, and either of two preferred lever constructions, as illustrated in respective FIGS. 2 and 3, may be utilized for this purpose. In either event, the base member 36 is formed with a slot 81 and an intersecting pin-receiving aperture 82. This construction enables the lower end of a support bar 83 to be pin jointed within the slot 81 as by a pin 84 (see FIG. 2) whereby the support bar 83 is freely swingable within the slot 81.

In the lever construction illustrated in FIGS. 2 and 4 a lever member 86 is pin jointed at fixed locations to the upper ends of the support bar 83 and the piston 44. Thus, the lever member 86 includes a bifurcated end portion afforded by a pair of links 87. The links are connected to the support member 83 by a rivet 88 and are connected to the upper end of the piston 44 by a bolt 89 and nut 91. The links 87 are also joined to a pipe or tube 92 which affords a socket for the reception of an end of a handle extension. In the arrangement illustrated in FIGS. 2 and 4, the rivet 88 serves as a fulcrum for the lever member 86, which is movable between the positions illustrated by the bold and phantom outlines in FIG. 2.

In some instances it may be desirable to vary the mechanical advantage afforded by the lever member 86, and in such an event the present invention contemplates the use of a lever construction like that illustrated in FIG. 3. Thus, and as pointed out in the above-noted Patent No. 2,885,961, it is often desirable to be able to raise the support carriage 24 at a more rapid rate when the carriage is unloaded or only lightly unloaded than when the carriage is heavily loaded, and the bell crank lever construction illustrated in FIG. 3 enables this mode of operation to be achieved. Insofar as the parts of the lever construction illustrated in FIG. 3 are like those illustrated in FIG. 2, like reference numerals are used but with the addition of the prime mark in FIG. 3. Thus, a support bar 83' is pin jointed at 84 in a slot formed in the base member as. A handle member 86 is pin jointed to the support bar 33 at 88. However, in the arrangement illustrated in FIG. 3 an adjusting link 91, which is formed with a series of notches N1, N2, N3, and N4 in a lower edge thereof, is also pin jointed at 88' to the support bar 83. A drive link 92 is pin jointed at 93 to the handle 86' and is pin jointed at 94 to the piston 44. Thus, the notches Nl-N4- enable the fulcrum 88' to be moved toward or away from the pin joint 94 to accordingly vary the mechanical advantage afforded by the lever construction illustrated in FIG. 3 in the manner indicated by the phantom positions illustrated in FIG. 3.

Thus, in accordance with this invention there is provided pump apparatus which is adapted to be installed or removed as a unitary assembly and which is especially adapted for use with manually powered and propelled lift trucks. The pump apparatus of the present invention is of a relatively simple construction but nevertheless achieves a high degree of flexibility in operation and also enables precise control of operation to be achieved. Additionally, the pump apparatus of the present invention is operative in either a horizontal or vertical position, or in any intermediate position, so that installation of the pump apparatus on the mechanism to be powered thereby is greatly facilitated. Furthermore, all operative parts of the pump apparatus are readily accessible from the outside to thereby facilitate any servicing or maintenance that may be necessary.

Hence, while I have illustrated and described the preferred embodiments of my invention, it is to be understood that these are capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claim.

I claim:

In a lift truck having a wheel supported base and an upright frame supporting a vertically movable lift carriage thereon, a hydraulically operated ram including a normally vertically operable cylinder and piston adapted to elevate the carriage, and pump apparatus including a manually operable piston for supplying fluid under pressure to said cylinder, said pump apparatus comprising: reservoir means for containing hydraulic fluid, said reser voir means including a tank having flat side walls including a forward side wall and top and bottom end walls, a base member having a flat forward face extending from a forward corner edge of the base member and integrally joined in a side Wall of the tank along the portion of the side wall which is immediately adjacent the bottom wall of the tank, said base member having conduit means formed therein, which conduit means include an outlet opening in the base member portion thereof other than in said flat face and interconnected passageways for conducting fluid between the tank and the outlet opening, and fluidpressurizing means including another cylinder integrally joined to said base member and a piston reciprocable within the cylinder for pumping hydraulic fluid from said tank through said outlet opening for supplying fluid under pressure to said cylinder, a handle connected to the piston of said other cylinder and having a free end projected beyond said base member in position to be grasped, said conduit means including a fluid inlet passageway extending from said fluid-pressuring means and opening at an inlet opening in said flat face of said base member in a location closely adjacent said forward corner edge of the 8. base member most remote from the free end of said handle and communicating with the reservoir afforded by the tank at a point closelyadjacent the forward side wall of the tank whereby the pump apparatus'is positionable on the lift truck with said handle in either an outermost substantially horizontal position or an uppermost substantially vertical position, with said inlet opening in either instance located at the bottom of the reservoir.

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